Throttle valve for pneumatic tools



July 20, 1937. w A s n- SR 2,087,583

THROTTLE VALVE FOR PNEUMATIC TOOLS ,Filed Aug. 12, 1936 2 Sheets-Sheet l INVENTOR H I S ATTO RNEY.

July 20, 1937. w. A. SMITH, SR 2,087;583

' THROTTLE VALVE FOR PNEUMATIC TOOLS Filed Aug. 12, 1956 2 Sheets-Sht 2 (95 5 .49 75 ii; :79 4 9 gw 58 I W J! 6 U IIH J3 46 82;

INVENTOR Maia/nil 5122111051 M4 MM HI 5 ATTORNEY.

Patented July 20, 1937 THROTTLE VALVE FOR PNEUMATIC TOOLS William A. Smith, Sr.,

Athens, Pa., assignor to ingersoll-Rand Company, Jersey City, N. 3., a corporation of New Jersey Application August 12, 1936, Serial No. 95,497

2 Claims.

This invention relates to throttle valves, and more particularly to a throttle valve for pneu matic tools.

One object of the invention is to reduce the overall length of the pneumatic tool.

Another object is to assure thorough lubrication of the throttle valve and its seating surfaces.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is an elevation, in section, of a rock drill equipped with a throttle valve constructed in accordance with the practice of the invention,

Figures 2, 3 and 4 are transverse Views taken through Figure l on the line 2-2 showing the throttle valve in different controlling positions,

Figure 5 is a View similar to Figure 1 showing a modified form of the invention, and

Figure 6 is a transverse view taken through Figure 5 on the line i5fi.

Referring more particularly to the drawings, 21] designates, in general, a pneumatic too-l of the percussive type adapted to actuate a working implement 2!.

The tool 26 comprises a cylinder 22 and front and back heads 23 and 2-3, respectively, which may be secured to the cylinder by the usual side bolts 25. Interposed between the cylinder 22 and the front head 23 is a front cylinder washer 26 which forms a closure for the front end of a piston chamber 2'! in the cylinder and also serves as a guide for the stem 28 of a hammer piston 29 reciprocable in the piston chamber for delivering blows to the working implement 2B.

In the stem 28 are a series of flutes 36 to accommodate ribs Si in a chuck 32 in the front head 23 and wherewith the working implement 2i is slidably interlocked. The cylinder 22 in the present instance is provided with a free exhaust port 33 which is controlled by the piston 29.

In the rearward portion of the cylinder 22 is an enlarged bore 3% for the accommodation of pressure fluid distributing valve mechanism 35 and rotation mechanism 35. The distributing valve mechanism is arranged adjacent the rear end of the piston chamber Zl. It comprises a valve chest consisting of a pair of plates 37 and 38 of which the plate 3? serves as a closure for the rear end of the piston chamber and has an inlet passage 39 which opens into the rear end of the piston chamber. An inlet passage 40, in the plate 3? and in the cylinder 22, leads to the front end of the piston chamber 27.

Both inlet passages communicate with a valve chamber 4! defined by the plates 3'? and 38 and containing a distributing valve Q2 of the oscillatory plate type for controlling the inlet passages 39 and 60.

The rotation mechanism 36 is seated upon the plate 38 and comprises a ratchet ring :33 which encircles the head M of a rifle bar 45 extending through the valve mechanism and interlockingly engaging the piston 29. The head Cid carries the usual spring pressed pawls ll; to engage teeth ii on the inner surface of the ratchet ring 33 for holding the rifle bar against rotary movement during the rearward stroke of the piston 2e and thereby enable the piston to describe a partial revolution, in a manner well known, for rotating the working implement 21 to a new position between blows of the hammer piston.

Preferably a plate 58 is interposed between the ratchet ring and the back head 24 to transmit the clamping pressure of the back head to the elements housed in the bore The plate 2 8, the ratchet ring 43 and the plate 38 are provided with supply passages 59 for conveying pressure fluid to the valve chamber ii, and the pressure fluid is supplied to the supply passages by a supply chamber 55 in the back head 24 and communicating with a supply conduit 5i through a port 52. i

In accordance with the practice of the invention the front end of the chamber 5e also serves as a chamber for a throttle valve 53 consisting of a flat plate having an axial bore 5% to receive a boss or spindle 55 on the front head. The

front end of the throttle valve 53 is seated upon a seating surface 5% on the rear end of the plate 48, and the rearward surface of the throttle valve constitutes a pressure area 57: against which pressure fluid in the chamber 5t acts constantly to maintain the throttle valve seated firmly against the plate $8.

In the throttle valve are a series of ports 58 which, when the throttle valve occupies one controlling position, register with the supply passages 49 to admit pressure fluid thereto from the chamber 59'. The ports 58 will also register with passages 59 in the plate 48 and the ratchet ring G3 and opening into an annular groove 65 in the periphery of the ratchet ring.

The annular groove 68 communicates with a blower passage iii, in the cylinder 22 and the front cylinder washer 25, leading to an internal annular groove 62 in the front cylinder washer. The passages 59 and 59 are arranged on the same circle and are staggered with respect to each other so that either set of passages may be readily communicated with pressure fluid supply by merely shifting the valve 53 a slight distance.

The means provided for actuating or rotating the valve 53 comprises a shaft $3 journalledin the back head 24 and having a flange 64 that engages a shoulder 65 in the back head to prevent rearward movement of the shaft; The flange 64 carries a stem fiifiwhich is arranged eccentrically with respect to the shaft 63 and extends into a' notch 67 in the periphery of the valve 53. The opposite end o-f the shaft is in the form of a reduced extension $8 upon which is mounted ale- J ver 69 for rotating the shaft 53. The end 68 is threaded forthe accommodation of a nut 18 whereby the IEVBTEQ is clamped firmly to the shaft 63. a V

The operation of the device is as follows: Whenever it is desired to set the distributing and percussive elements of the pneumatic tool in operation the throttle valve is rotated, by means of the lever 69, to a position in which the ports '58 register with the passages Q3, as illustrated in Figure 3. Pressure fluid is thereby admitted into the valve chamber ll and distributed to the ends of the piston chamber by the valve 42 to cause reciprocation of the piston 23.

In the event that such means as may be pro- Vided for normally maintaining the drill hole free of detritus prove inadequateforethat purpose,

and in consequence of which cuttings accumulate in the drill hole, the throttle valve 53 is'rotated to another controlling position in which the ports 58 register with the passages 59. This position is illustrated in Figure l. Pressurefiuid will then flow directly from supply into the annular groove 52, thence through the flutes 3B, the chuck 32 and through the working implement into the drill hole to expel the cuttings therefrom. After the drill hole has been cleansed the throttle valve 53 may again be returned to its initial position, or to a neutral position in which the ports 58 are out or" registry with the passages V eral flange l5 which seats upon a'seating surface 16' on the ratchet ring. The rearward surface of the flange l5 constitutes a pressure area 11 against which pressure fluid in the chamber 12 acts to press the flange l5 against the seating surface It. The'flange, as in the form, of the throttle valve previously described, is also provided with a series of ports tit to register with the supply passages 139 and the blower passages In the present instance the valve actuator is" arranged in the same transverse plane as the flange 75. It comprises a worm 18 of which the thread is of a self-locking pitch and engages teeth "I9 on the periphery of the flange 15. The ends of the Worm are provided with stems B0 and 8| of which the latter is journalled in a plug 83 by a nut 85.

In the operation of this form of valve the worm 18 is rotated by'means of the lever 84 to bring ,the ports 58 into registry with the passages 49 or 59, depending upon whether it be intended to supply pressure fluid to the distributing valve 42 for operating the percussive element or to the blower passages for cleansing the drill hole. The worm is rotated in one direction to communicate the passages 49 with pressure fluid supply and in an opposite direction to supply pressure fluid to the passages 59. By reason of the .fact that the threads of the Worm are of a self-locking pitch the throttle valve '13 will remain securely in placed position undisturbed by thevibrationsiresulting from the operation of the rock drill.

In practice, the present invention has been found to be highly desirable in pneumatic tools. By arranging the throttle valve in the path of flow of the pressure fluid conveying lubricant for will be constantly supplied with an ample amount of lubricant, thereby preventing sticking of the throttle valve and rendering it particularly easy to manipulate, i

I claim:

1. In'a, throttle valve for pneumatic tools, the combination of a casing and a pressure fluidldistributing element, a passage to convey cleansing fluid for cleansing a hole being drilled, a supply passage for conveying pressure fluid to the distributing element; a rotary plate throttle valve in the casing having a port to afford communication between pressure fluid supply and the passages, and rneans for rotating theth'rottle valve to place the port selectively in registry with the passages. ,7 V

2. In a throttle valve for pneumatic tools, the

combination of a casing and rotation mechanism therein including'a ratchet ring, a seating surface on the ratchet ring, a pressure fluid distributing element, a supply passage for conveying pressurefluid to the distributing element, a passage ior conveying cleansing fluid for cleansing a hole being drilled, an annular plate throttle valve on the seating surface encircling the ratchet ring and having a port to selectively efthe bearing surfaces of the tool theethrottle valve 

